From: Nicolin Chen <nicolinc@nvidia.com>
To: "Tian, Kevin" <kevin.tian@intel.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>,
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Subject: Re: [PATCH 3/5] vfio/iommu_type1: Prefer to reuse domains vs match enforced cache coherency
Date: Tue, 14 Jun 2022 13:45:18 -0700 [thread overview]
Message-ID: <YqjzXpzuBa4ATf9o@Asurada-Nvidia> (raw)
In-Reply-To: <DM4PR11MB52781590FB8FB197579DEE848CA49@DM4PR11MB5278.namprd11.prod.outlook.com>
Hi Kevin,
On Wed, Jun 08, 2022 at 11:48:27PM +0000, Tian, Kevin wrote:
> > > > The KVM mechanism for controlling wbinvd is only triggered during
> > > > kvm_vfio_group_add(), meaning it is a one-shot test done once the
> > devices
> > > > are setup.
> > >
> > > It's not one-shot. kvm_vfio_update_coherency() is called in both
> > > group_add() and group_del(). Then the coherency property is
> > > checked dynamically in wbinvd emulation:
> >
> > From the perspective of managing the domains that is still
> > one-shot. It doesn't get updated when individual devices are
> > added/removed to domains.
>
> It's unchanged per-domain but dynamic per-vm when multiple
> domains are added/removed (i.e. kvm->arch.noncoherent_dma_count).
> It's the latter being checked in the kvm.
I am going to send a v2, yet not quite getting the point here.
Meanwhile, Jason is on leave.
What, in your opinion, would be an accurate description here?
Thanks
Nic
next prev parent reply other threads:[~2022-06-14 20:45 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-06 6:19 [PATCH 0/5] Simplify vfio_iommu_type1 attach/detach routine Nicolin Chen
2022-06-06 6:19 ` [PATCH 1/5] iommu: Return -EMEDIUMTYPE for incompatible domain and device/group Nicolin Chen
2022-06-07 3:23 ` Baolu Lu
2022-06-07 4:03 ` Nicolin Chen
2022-06-08 7:49 ` Tian, Kevin
2022-06-08 17:38 ` Nicolin Chen
2022-06-06 6:19 ` [PATCH 2/5] iommu: Ensure device has the same iommu_ops as the domain Nicolin Chen
2022-06-06 14:33 ` Robin Murphy
2022-06-06 16:51 ` Nicolin Chen
2022-06-06 17:50 ` Robin Murphy
2022-06-06 18:28 ` Nicolin Chen
2022-06-06 18:52 ` Jason Gunthorpe
2022-06-06 6:19 ` [PATCH 3/5] vfio/iommu_type1: Prefer to reuse domains vs match enforced cache coherency Nicolin Chen
2022-06-08 8:28 ` Tian, Kevin
2022-06-08 11:17 ` Jason Gunthorpe
2022-06-08 23:48 ` Tian, Kevin
2022-06-14 20:45 ` Nicolin Chen [this message]
2022-06-15 7:35 ` Tian, Kevin
2022-06-15 23:12 ` Nicolin Chen
2022-06-06 6:19 ` [PATCH 4/5] vfio/iommu_type1: Clean up update_dirty_scope in detach_group() Nicolin Chen
2022-06-08 8:35 ` Tian, Kevin
2022-06-08 17:46 ` Nicolin Chen
2022-06-06 6:19 ` [PATCH 5/5] vfio/iommu_type1: Simplify group attachment Nicolin Chen
2022-06-07 7:44 ` [PATCH 0/5] Simplify vfio_iommu_type1 attach/detach routine Baolu Lu
2022-06-07 11:58 ` Jason Gunthorpe
2022-06-07 12:42 ` Baolu Lu
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